1. Field of the Invention
The present invention concerns an automatic anti-fall device for power-driven lifting machinery; its use is more particularly adapted to equipping scaffolding nacelles.
2. Description of the Prior Art
Devices have already been proposed for use with lifting machinery, either solely in the event of a break in a cable-type lifting machine, or also in the event of a break in the bearer cable, in the anchoring appliance or in any part of the suspension gear, by using an auxiliary safety cable, which carries the load when any breakdown occurs on the main suspension.
The devices already proposed comprise, for example, a block of self-clamping jaws subject to pre-clamping which is subsequently cancelled by the action of the load on a rod system during normal operations, whereas these jaws are clamped together rapidly on the bearer cable or on the safety cable in the event of any breakdown on the normal suspension.